i can see my map

but some of my players can't please fix.

You should use the Help Center and Send a request to get Roll20 staff attention and a ticket to track your issue. It’s mostly community help here.  I would check that you haven’t got basic Fog of War enabled on that Page. I always do, and I have to remember to reveal the map area during prep of my players see a black map. 

Another few things to check, besides Fog of War: 1. Is the map on the map layer? If it is on the GM layer, move it to the map layer. 2. Is the map image in your art library under "Recent Uploads"? If it somehow got deleted from there, it will go away on the virtual tabletop (sooner or later, once that image is no longer cached). 3. Are all your players on the same map page? (Nice avatar, by the way!)

Maxfire said: but some of my players can't please fix. Here's my standard vision/lighting troubleshooting checklist.  Make sure you are using Chrome or Firefox. Make sure you are set to only use either Updated Dynamic Lighting or Legacy Dynamic Lighting, not both. Token must have vision enabled. Token must be 'controlled' by the player who is checking vision. You should use a ' dummy account ' in order to see changes live/instantaneously when you make them as GM. There are other benefits as well (streaming, testing macros and other tricks, resetting the game URL). There needs to be a light source. Tokens always emit light from the center of the token -- in LDL it comes from a small point in the center of the image, and in UDL it comes from a circle that is some small percentage of the image size -- so if you set the map image as a light source, you'll get some funky behavior. Token and light source need to be on the correct layers. Do not use .webm animated tokens. They are currently bugged and often will not work correctly and prevent visibility. If a player cannot see, move their token. There is a bug with UDL that prevents player vision from 'activating' until after one of their tokens is moved on a page. Make sure you don't have a Fog of War/Permanent Darkness layer on. Make sure you don't have Advanced Fog of War/Explorable Darkness blocking vision. Explorable Darkness and Advanced Fog of War are saved for each token. So if a player has control of a token, they will see all of their 'explored area'. Page 'Cell Width' settings can have an affect on a token's vision, especially if the 'light multiplier' is set to something other than 100%. Switch the Cell Width to '1' and see what happens. Check random other page settings, such as 'Restrict Movement' Make sure your view is centered on a token that has vision enabled and a light source Make sure you/your players are on the correct page. Double check that they have not been split from the Party ribbon. Clear your browser cache. Clear the game chat archive.

Is the map actually loading or is the game stuck at the loading screen and are they on a PC (desktop or laptop) or ona tablet.  A problem a couple of my players have noticed and I've mangaged to replicate is that when using a tablet for a map with Dynamic lighting turned on the map won't load.  A complex large map without any DL loads fine, but just a blank white sheet with a few tokens on it with DL turned on refuses to load on my IPad Pro, but is fine on my desktop PC.